adapted comments and votes handlers

migrations/001_initial_schema.sql

@@ -35,7 +35,7 @@ COMMENT ON TABLE municipalities IS 'Configuration Per Municipality (Tenant) usin
 
 -- ---------------------------------------------------------------------
 -- Block 3: Table "contributions"
--- Aitizen and Administration Contributions as Points, Lines, and
+-- Citizen and Administration Contributions as Points, Lines, and
 -- Polygons stored together in one mixed-geometry Column.
 -- ---------------------------------------------------------------------
 CREATE TABLE contributions (

migrations/009_tasks-module.sql

@@ -0,0 +1,183 @@
+-- =====================================================================
+-- Migration 009: Tasks Module — Tasks with Reward System
+-- =====================================================================
+
+
+-- ---------------------------------------------------------------------
+-- Block 1: Tasks Table
+-- Stores Tasks with Geometry, Moderation and Completion.
+-- Status Flow from pending to rejected or approved to completed to verified
+-- ---------------------------------------------------------------------
+CREATE TABLE IF NOT EXISTS tasks (
+    task_id              SERIAL PRIMARY KEY,
+    municipality_id      INTEGER NOT NULL REFERENCES municipalities(municipality_id),
+    geom                 GEOMETRY(Geometry, 4326) NOT NULL,
+    geom_type            VARCHAR(10) NOT NULL CHECK (geom_type IN ('point', 'line', 'polygon')),
+    category             VARCHAR(50) NOT NULL,
+    title                VARCHAR(200) NOT NULL,
+    description          TEXT DEFAULT '',
+    points_reward        INTEGER NOT NULL DEFAULT 25,
+    author_name          VARCHAR(100) NOT NULL,
+    browser_id           VARCHAR(36),
+    photo_path           VARCHAR(255),
+    status               VARCHAR(20) NOT NULL DEFAULT 'pending'
+                         CHECK (status IN ('pending', 'rejected', 'approved', 'completed', 'verified')),
+    address              VARCHAR(255),
+
+    -- Completion Fields empty before completed
+    completed_by_name    VARCHAR(100),
+    completed_by_browser VARCHAR(36),
+    completion_photo     VARCHAR(255),
+    completion_comment   TEXT,
+    completed_at         TIMESTAMP,
+
+    -- Counters updated via Triggers
+    likes_count          INTEGER NOT NULL DEFAULT 0,
+    dislikes_count       INTEGER NOT NULL DEFAULT 0,
+    comment_count        INTEGER NOT NULL DEFAULT 0,
+
+    created_at           TIMESTAMP NOT NULL DEFAULT NOW(),
+    updated_at           TIMESTAMP NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_tasks_municipality ON tasks(municipality_id);
+CREATE INDEX idx_tasks_status ON tasks(status);
+CREATE INDEX idx_tasks_category ON tasks(category);
+
+
+-- ---------------------------------------------------------------------
+-- Block 2: Citizen Points Table
+-- One Row per Completion. Leaderboard via SUM and GROUP BY.
+-- ---------------------------------------------------------------------
+CREATE TABLE IF NOT EXISTS user_points (
+    points_id            SERIAL PRIMARY KEY,
+    municipality_id      INTEGER NOT NULL REFERENCES municipalities(municipality_id),
+    user_name            VARCHAR(100) NOT NULL,
+    points               INTEGER NOT NULL DEFAULT 25,
+    task_id              INTEGER NOT NULL REFERENCES tasks(task_id) ON DELETE CASCADE,
+    created_at           TIMESTAMP NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_user_points_municipality ON user_points(municipality_id);
+CREATE INDEX idx_user_points_user ON user_points(user_name);
+
+
+-- ---------------------------------------------------------------------
+-- Block 3: Adapts Votes Table for Tasks
+-- Either contribution_id OR task_id
+-- ---------------------------------------------------------------------
+ALTER TABLE votes
+    ADD COLUMN task_id INTEGER REFERENCES tasks(task_id) ON DELETE CASCADE;
+
+CREATE INDEX idx_votes_task ON votes(task_id);
+
+-- Unique Vote per Browser per Task
+ALTER TABLE votes
+    ADD CONSTRAINT votes_task_browser_unique
+    UNIQUE (task_id, browser_id);
+
+
+-- ---------------------------------------------------------------------
+-- Block 4: Adapts Comments Table for Tasks
+-- Either contribution_id OR task_id
+-- ---------------------------------------------------------------------
+ALTER TABLE comments
+    ADD COLUMN task_id INTEGER REFERENCES tasks(task_id) ON DELETE CASCADE;
+
+CREATE INDEX idx_comments_task ON comments(task_id);
+
+
+-- ---------------------------------------------------------------------
+-- Block 5: Trigger Updated Timestamp for Tasks
+-- ---------------------------------------------------------------------
+CREATE TRIGGER set_tasks_updated_at
+    BEFORE UPDATE ON tasks
+    FOR EACH ROW
+    EXECUTE FUNCTION set_updated_at();
+
+
+-- ---------------------------------------------------------------------
+-- Block 6: Trigger Vote Counts for Tasks
+-- Mirrors Pattern from Contributions.
+-- ---------------------------------------------------------------------
+CREATE OR REPLACE FUNCTION update_task_vote_counts()
+RETURNS TRIGGER AS $$
+BEGIN
+    IF TG_OP = 'INSERT' OR TG_OP = 'UPDATE' THEN
+        IF NEW.task_id IS NOT NULL THEN
+            UPDATE tasks SET
+                likes_count = (SELECT COUNT(*) FROM votes WHERE task_id = NEW.task_id AND vote_type = 'like'),
+                dislikes_count = (SELECT COUNT(*) FROM votes WHERE task_id = NEW.task_id AND vote_type = 'dislike')
+            WHERE task_id = NEW.task_id;
+        END IF;
+    END IF;
+
+    IF TG_OP = 'DELETE' OR (TG_OP = 'UPDATE' AND OLD.task_id IS NOT NULL) THEN
+        UPDATE tasks SET
+            likes_count = (SELECT COUNT(*) FROM votes WHERE task_id = OLD.task_id AND vote_type = 'like'),
+            dislikes_count = (SELECT COUNT(*) FROM votes WHERE task_id = OLD.task_id AND vote_type = 'dislike')
+        WHERE task_id = OLD.task_id;
+    END IF;
+
+    RETURN NULL;
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS trigger_update_task_vote_counts ON votes;
+
+CREATE TRIGGER trigger_update_task_vote_counts
+    AFTER INSERT OR DELETE OR UPDATE ON votes
+    FOR EACH ROW
+    EXECUTE FUNCTION update_task_vote_counts();
+
+
+-- ---------------------------------------------------------------------
+-- Block 7: Trigger Comment Count for Tasks
+-- Mirrors Pattern from Contributions.
+-- ---------------------------------------------------------------------
+CREATE OR REPLACE FUNCTION update_task_comment_count()
+RETURNS TRIGGER AS $$
+BEGIN
+    IF TG_OP = 'INSERT' OR TG_OP = 'UPDATE' THEN
+        IF NEW.task_id IS NOT NULL THEN
+            UPDATE tasks
+            SET comment_count = (
+                SELECT COUNT(*) FROM comments
+                WHERE task_id = NEW.task_id AND status = 'approved'
+            )
+            WHERE task_id = NEW.task_id;
+        END IF;
+    END IF;
+
+    IF TG_OP = 'DELETE' OR (TG_OP = 'UPDATE' AND OLD.task_id IS NOT NULL) THEN
+        UPDATE tasks
+        SET comment_count = (
+            SELECT COUNT(*) FROM comments
+            WHERE task_id = OLD.task_id AND status = 'approved'
+        )
+        WHERE task_id = OLD.task_id;
+    END IF;
+
+    RETURN NULL;
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS trigger_update_task_comment_count ON comments;
+
+CREATE TRIGGER trigger_update_task_comment_count
+    AFTER INSERT OR DELETE OR UPDATE OF status ON comments
+    FOR EACH ROW
+    EXECUTE FUNCTION update_task_comment_count();
+
+
+-- ---------------------------------------------------------------------
+-- Block 8: Views for QGIS
+-- ---------------------------------------------------------------------
+CREATE OR REPLACE VIEW tasks_points AS
+    SELECT * FROM tasks WHERE geom_type = 'point';
+
+CREATE OR REPLACE VIEW tasks_lines AS
+    SELECT * FROM tasks WHERE geom_type = 'line';
+
+CREATE OR REPLACE VIEW tasks_polygons AS
+    SELECT * FROM tasks WHERE geom_type = 'polygon';

public/api/contributions.php

@@ -17,7 +17,7 @@ require_once __DIR__ . '/db.php';
 
 
 // ---------------------------------------------------------------------
-// Read Action Parameter and Route to correct Handler
+// Reads Action Parameter and Routes to correct Handler
 // ---------------------------------------------------------------------
 $input = get_input();
 $action = $input['action'] ?? '';
@@ -59,6 +59,27 @@ switch ($action) {
     case 'update_comment':
         handle_update_comment($input);
         break;
+    case 'read_tasks':
+        handle_read_tasks($input);
+        break;
+    case 'create_task':
+        handle_create_task($input);
+        break;
+    case 'update_task':
+        handle_update_task($input);
+        break;
+    case 'delete_task':
+        handle_delete_task($input);
+        break;
+    case 'complete_task':
+        handle_complete_task($input);
+        break;
+    case 'verify_task':
+        handle_verify_task($input);
+        break;
+    case 'read_leaderboard':
+        handle_read_leaderboard($input);
+        break;
     default:
         error_response('Unknown Action. Supported Actions are read, create, update, delete, vote.');
 }
@@ -335,8 +356,8 @@ function handle_delete($input) {
 
 
 // ---------------------------------------------------------------------
-// VOTE: Likes or Dislikes a Contribution
-// Required: contribution_id, voter_name, vote_type
+// VOTE: Likes or Dislikes Contributions or Tasks
+// Required: contribution_id or task_id, voter_name, vote_type
 // Database Trigger automatically updates Likes and Dislikes Count
 // UNIQUE Constraint prevents duplicate Votes per Voter.
 // ---------------------------------------------------------------------
@@ -344,7 +365,7 @@ function handle_vote($input) {
     $pdo = get_db();
 
     // Validates Input
-    $missing = validate_required($input, ['contribution_id', 'voter_name', 'vote_type']);
+    $missing = validate_required($input, ['voter_name', 'vote_type']);
     if (!empty($missing)) {
         error_response('Missing Fields: ' . implode(', ', $missing));
     }
@@ -355,13 +376,6 @@ function handle_vote($input) {
         error_response('Invalid vote_type. Must be: ' . implode(', ', $valid_vote_types));
     }
 
-    // Checks if Contribution exists
-    $stmt = $pdo->prepare("SELECT contribution_id FROM contributions WHERE contribution_id = :id");
-    $stmt->execute([':id' => $input['contribution_id']]);
-    if (!$stmt->fetch()) {
-        error_response('Contribution not found.', 404);
-    }
-
     // Prepared SQL Statement
     try {
         // Checks if Voter already voted on this Contribution
@@ -370,11 +384,39 @@ function handle_vote($input) {
             error_response('Browser ID required for Voting.');
         }
 
+        // Determines Vote Type
+        $is_task = isset($input['task_id']) && $input['task_id'] !== '';
+
+        if ($is_task) {
+            // Checks for Tasks
+            $stmt = $pdo->prepare("SELECT task_id FROM tasks WHERE task_id = :id");
+            $stmt->execute([':id' => $input['task_id']]);
+            if (!$stmt->fetch()) {
+                error_response('Task not found.', 404);
+            }
+
+            // Checks if Browser already voted on Task
             $stmt = $pdo->prepare("
                 SELECT vote_id, vote_type FROM votes
-            WHERE contribution_id = :cid AND browser_id = :bid
+                WHERE task_id = :id AND browser_id = :bid
             ");
-        $stmt->execute([':cid' => $input['contribution_id'], ':bid' => $browser_id]);
+            $stmt->execute([':id' => $input['task_id'], ':bid' => $browser_id]);
+        } else {
+            // Checks for Contributions
+            $stmt = $pdo->prepare("SELECT contribution_id FROM contributions WHERE contribution_id = :id");
+            $stmt->execute([':id' => $input['contribution_id']]);
+            if (!$stmt->fetch()) {
+                error_response('Contribution not found.', 404);
+            }
+
+            // Checks if Browser already voted on Contribution
+            $stmt = $pdo->prepare("
+                SELECT vote_id, vote_type FROM votes
+                WHERE contribution_id = :id AND browser_id = :bid
+            ");
+            $stmt->execute([':id' => $input['contribution_id'], ':bid' => $browser_id]);
+        }
+
         $existing = $stmt->fetch();
 
         if ($existing) {
@@ -384,36 +426,48 @@ function handle_vote($input) {
                 $stmt->execute([':vid' => $existing['vote_id']]);
                 json_response(['message' => 'Vote removed.', 'action' => 'removed']);
             } else {
-                // Different Vote Type — Switches Vote
+                // Different Vote Type — Removes old Vote before Inserting new one
                 $stmt = $pdo->prepare("DELETE FROM votes WHERE vote_id = :vid");
                 $stmt->execute([':vid' => $existing['vote_id']]);
-
-                $stmt = $pdo->prepare("
-                    INSERT INTO votes (contribution_id, voter_name, vote_type, browser_id)
-                    VALUES (:cid, :voter, :vtype, :bid)
-                ");
-                $stmt->execute([
-                    ':cid'   => $input['contribution_id'],
-                    ':voter' => $input['voter_name'],
-                    ':vtype' => $input['vote_type'],
-                    ':bid'   => $browser_id
-                ]);
-                json_response(['message' => 'Vote changed.', 'action' => 'changed'], 200);
+                $this_insert = true;
             }
         } else {
             // No existing Vote — Inserts Vote
+            $this_insert = true;
+        }
+
+        if (!empty($this_insert)) {
+            if ($is_task) {
                 $stmt = $pdo->prepare("
-                    INSERT INTO votes (contribution_id, voter_name, vote_type, browser_id)
-                    VALUES (:cid, :voter, :vtype, :bid)
+                    INSERT INTO votes (task_id, voter_name, vote_type, browser_id)
+                    VALUES (:id, :voter, :vtype, :bid)
                 ");
                 $stmt->execute([
-                    ':cid'   => $input['contribution_id'],
+                    ':id'    => $input['task_id'],
                     ':voter' => $input['voter_name'],
                     ':vtype' => $input['vote_type'],
                     ':bid'   => $browser_id
                 ]);
+            } else {
+                $stmt = $pdo->prepare("
+                    INSERT INTO votes (contribution_id, voter_name, vote_type, browser_id)
+                    VALUES (:id, :voter, :vtype, :bid)
+                ");
+                $stmt->execute([
+                    ':id'    => $input['contribution_id'],
+                    ':voter' => $input['voter_name'],
+                    ':vtype' => $input['vote_type'],
+                    ':bid'   => $browser_id
+                ]);
+            }
+
+            // Returns changed or created
+            if ($existing) {
+                json_response(['message' => 'Vote changed.', 'action' => 'changed'], 200);
+            } else {
                 json_response(['message' => 'Vote recorded.', 'action' => 'created'], 201);
             }
+        }
 
     } catch (PDOException $e) {
         error_response('Database Error: ' . $e->getMessage(), 500);
@@ -565,26 +619,40 @@ function handle_photo_upload($file) {
 // =====================================================================
 
 // ---------------------------------------------------------------------
-// READ COMMENTS: Loads Comments for a Contribution
-// Returns Comments sorted by Date (newest first)
-// Required: contribution_id
+// READ COMMENTS: Loads Comments for Contributions or Tasks
+// Returns Comments sorted by Date (oldest first)
+// Required: contribution_id or task_id
 // ---------------------------------------------------------------------
 function handle_read_comments($input) {
     $pdo = get_db();
 
-    $missing = validate_required($input, ['contribution_id']);
-    if (!empty($missing)) {
-        error_response('Missing Fields: ' . implode(', ', $missing));
+    // Checks for contribution_id or task_id
+    if (empty($input['contribution_id']) && empty($input['task_id'])) {
+        error_response('Either contribution_id or task_id is required.');
     }
 
+    // Determines Vote Type
+    $is_task = isset($input['task_id']) && $input['task_id'] !== '';
+
     try {
+        if ($is_task) {
+            $stmt = $pdo->prepare("
+                SELECT comment_id, task_id, author_name, browser_id, content, status, created_at
+                FROM comments
+                WHERE task_id = :id AND status = 'approved'
+                ORDER BY created_at ASC
+            ");
+        } else {
             $stmt = $pdo->prepare("
                 SELECT comment_id, contribution_id, author_name, browser_id, content, status, created_at
                 FROM comments
-            WHERE contribution_id = :cid AND status = 'approved'
+                WHERE contribution_id = :id AND status = 'approved'
                 ORDER BY created_at ASC
             ");
-        $stmt->execute([':cid' => $input['contribution_id']]);
+        }
+        
+        // Prepared Statement
+        $stmt->execute([':id' => $is_task ? $input['task_id'] : $input['contribution_id']]);
         $comments = $stmt->fetchAll();
 
         json_response(['comments' => $comments, 'count' => count($comments)]);
@@ -596,37 +664,56 @@ function handle_read_comments($input) {
 
 
 // ---------------------------------------------------------------------
-// CREATE COMMENT: Adds Comments to Contributions
-// Required: contribution_id, author_name, content
+// CREATE COMMENT: Adds Comments Contributions or Tasks
+// Required: author_name, content, contribution_id or task_id
 // Optional: browser_id
 // ---------------------------------------------------------------------
 function handle_create_comment($input) {
     $pdo = get_db();
 
-    $missing = validate_required($input, ['contribution_id', 'author_name', 'content']);
+    $missing = validate_required($input, ['author_name', 'content']);
     if (!empty($missing)) {
         error_response('Missing Fields: ' . implode(', ', $missing));
     }
 
-    // Validates Content Length
+    // Checks for contribution_id or task_id
+    if (empty($input['contribution_id']) && empty($input['task_id'])) {
+        error_response('Either contribution_id or task_id is required.');
+    }
+
+    // Validates Length
     if (strlen($input['content']) > 1000) {
         error_response('Comment too long. Maximum 1000 Characters.');
     }
 
-    // Checks if Contribution exists
+    // Determines Comment Type
+    $is_task = isset($input['task_id']) && $input['task_id'] !== '';
+
+    if ($is_task) {
+        // Checks for Tasks
+        $stmt = $pdo->prepare("SELECT task_id FROM tasks WHERE task_id = :id");
+        $stmt->execute([':id' => $input['task_id']]);
+        if (!$stmt->fetch()) {
+            error_response('Task not found.', 404);
+        }
+    } else {
+        // Checks for Contributions
         $stmt = $pdo->prepare("SELECT contribution_id FROM contributions WHERE contribution_id = :id");
         $stmt->execute([':id' => $input['contribution_id']]);
         if (!$stmt->fetch()) {
             error_response('Contribution not found.', 404);
         }
+    }
     
+    // Prepared Statement
     try {
         $stmt = $pdo->prepare("
-            INSERT INTO comments (contribution_id, author_name, browser_id, content)
-            VALUES (:cid, :author, :bid, :content)
+            INSERT INTO comments (contribution_id, task_id, author_name, browser_id, content)
+            VALUES (:cid, :tid, :author, :bid, :content)
         ");
         $stmt->execute([
-            ':cid'     => $input['contribution_id'],
+            ':cid'     => $is_task ? null : $input['contribution_id'],
+            ':tid'     => $is_task ? $input['task_id'] : null,
             ':author'  => $input['author_name'],
             ':bid'     => $input['browser_id'] ?? null,
             ':content' => $input['content']
@@ -710,3 +797,386 @@ function handle_update_comment($input) {
         error_response('Database Error: ' . $e->getMessage(), 500);
     }
 }
+
+
+// =====================================================================
+// Action Handlers for Tasks
+// =====================================================================
+
+
+// ---------------------------------------------------------------------
+// READ TASKS: Loads Tasks as GeoJSON FeatureCollection
+// Required: municipality_id
+// Optional: status, browser_id
+// ---------------------------------------------------------------------
+function handle_read_tasks($input) {
+    $pdo = get_db();
+
+    $missing = validate_required($input, ['municipality_id']);
+    if (!empty($missing)) {
+        error_response('Missing Fields: ' . implode(', ', $missing));
+    }
+
+    $sql = "SELECT *, ST_AsGeoJSON(geom) AS geojson
+            FROM tasks
+            WHERE municipality_id = :mid";
+    $params = [':mid' => $input['municipality_id']];
+
+    // Status Filter
+    $status = $input['status'] ?? 'visible';
+    if ($status === 'visible') {
+        $sql .= " AND status IN ('open', 'completed', 'verified')";
+    } elseif ($status !== 'all') {
+        $sql .= " AND status = :status";
+        $params[':status'] = $status;
+    }
+
+    $sql .= " ORDER BY created_at DESC";
+
+    try {
+        $stmt = $pdo->prepare($sql);
+        $stmt->execute($params);
+        $rows = $stmt->fetchAll();
+    } catch (PDOException $e) {
+        error_response('Database Error: ' . $e->getMessage(), 500);
+    }
+
+    // Builds GeoJSON FeatureCollection
+    $features = [];
+    foreach ($rows as $row) {
+        $geometry = json_decode($row['geojson']);
+        unset($row['geom'], $row['geojson']);
+        $features[] = [
+            'type'       => 'Feature',
+            'geometry'   => $geometry,
+            'properties' => $row
+        ];
+    }
+
+    $result = [
+        'type'     => 'FeatureCollection',
+        'features' => $features
+    ];
+
+    // User Votes for Tasks
+    $browser_id = $input['browser_id'] ?? '';
+    if ($browser_id !== '') {
+        $stmt = $pdo->prepare("
+            SELECT task_id, vote_type FROM votes
+            WHERE browser_id = :bid AND task_id IS NOT NULL
+        ");
+        $stmt->execute([':bid' => $browser_id]);
+        $user_votes = [];
+        foreach ($stmt->fetchAll() as $v) {
+            $user_votes[$v['task_id']] = $v['vote_type'];
+        }
+        $result['user_votes'] = $user_votes;
+    }
+
+    json_response($result);
+}
+
+
+// ---------------------------------------------------------------------
+// CREATE TASK: Inserts new Task with optional Photo
+// Required: municipality_id, geom, geom_type, category, title, author_name
+// Optional: description, browser_id, photo
+// ---------------------------------------------------------------------
+function handle_create_task($input) {
+    $pdo = get_db();
+
+    $missing = validate_required($input, [
+        'municipality_id', 'geom', 'geom_type', 'category', 'title', 'author_name'
+    ]);
+    if (!empty($missing)) {
+        error_response('Missing Fields: ' . implode(', ', $missing));
+    }
+
+    $valid_geom_types = ['point', 'line', 'polygon'];
+    if (!in_array($input['geom_type'], $valid_geom_types)) {
+        error_response('Invalid Geometry Type.');
+    }
+
+    $geojson = json_decode($input['geom']);
+    if (!$geojson || !isset($geojson->type)) {
+        error_response('Invalid GeoJSON.');
+    }
+
+    // Handles optional Photo Upload
+    $photo_path = null;
+    if (isset($_FILES['photo']) && $_FILES['photo']['error'] === UPLOAD_ERR_OK) {
+        $photo_path = handle_photo_upload($_FILES['photo']);
+        if (!$photo_path) {
+            error_response('Photo Upload failed. JPG, PNG, GIF and WebP up to 5 MB.');
+        }
+    }
+
+    try {
+        $stmt = $pdo->prepare("
+            INSERT INTO tasks
+                (municipality_id, geom, geom_type, category, title, description, author_name, browser_id, photo_path)
+            VALUES
+                (:mid, ST_SetSRID(ST_GeomFromGeoJSON(:geom), 4326), :geom_type,
+                 :category, :title, :description, :author_name, :browser_id, :photo_path)
+        ");
+        $stmt->execute([
+            ':mid'         => $input['municipality_id'],
+            ':geom'        => $input['geom'],
+            ':geom_type'   => $input['geom_type'],
+            ':category'    => $input['category'],
+            ':title'       => $input['title'],
+            ':description' => $input['description'] ?? '',
+            ':author_name' => $input['author_name'],
+            ':browser_id'  => $input['browser_id'] ?? null,
+            ':photo_path'  => $photo_path
+        ]);
+
+        json_response([
+            'message' => 'Task created successfully.',
+            'task_id' => (int) $pdo->lastInsertId()
+        ], 201);
+
+    } catch (PDOException $e) {
+        error_response('Database Error: ' . $e->getMessage(), 500);
+    }
+}
+
+
+// ---------------------------------------------------------------------
+// UPDATE TASK: Updates existing Tasks or Status
+// Required: task_id
+// Optional: category, title, description, status, address
+// ---------------------------------------------------------------------
+function handle_update_task($input) {
+    $pdo = get_db();
+
+    $missing = validate_required($input, ['task_id']);
+    if (!empty($missing)) {
+        error_response('Missing Fields: ' . implode(', ', $missing));
+    }
+
+    $updatable = ['category', 'title', 'description', 'status', 'address'];
+    $set = [];
+    $params = [':id' => $input['task_id']];
+
+    foreach ($updatable as $field) {
+        if (isset($input[$field]) && $input[$field] !== '') {
+            $set[] = "$field = :$field";
+            $params[":$field"] = $input[$field];
+        }
+    }
+
+    if (empty($set)) {
+        error_response('No Fields to update.');
+    }
+
+    if (isset($params[':status'])) {
+        $valid = ['pending', 'rejected', 'open', 'completed', 'verified'];
+        if (!in_array($params[':status'], $valid)) {
+            error_response('Invalid Status.');
+        }
+    }
+
+    try {
+        $stmt = $pdo->prepare("UPDATE tasks SET " . implode(', ', $set) . " WHERE task_id = :id");
+        $stmt->execute($params);
+        json_response(['message' => 'Task updated successfully.']);
+    } catch (PDOException $e) {
+        error_response('Database Error: ' . $e->getMessage(), 500);
+    }
+}
+
+
+// ---------------------------------------------------------------------
+// DELETE TASK: Removes existing Tasks
+// Required: task_id
+// ---------------------------------------------------------------------
+function handle_delete_task($input) {
+    $pdo = get_db();
+
+    $missing = validate_required($input, ['task_id']);
+    if (!empty($missing)) {
+        error_response('Missing Fields: ' . implode(', ', $missing));
+    }
+
+    try {
+        $stmt = $pdo->prepare("DELETE FROM tasks WHERE task_id = :id");
+        $stmt->execute([':id' => $input['task_id']]);
+        json_response(['message' => 'Task deleted successfully.']);
+    } catch (PDOException $e) {
+        error_response('Database Error: ' . $e->getMessage(), 500);
+    }
+}
+
+
+// ---------------------------------------------------------------------
+// COMPLETE TASK: Completes existing Tasks with Photo Proof
+// Required: task_id, author_name, browser_id
+// Required File: completion_photo
+// Optional: completion_comment
+// ---------------------------------------------------------------------
+function handle_complete_task($input) {
+    $pdo = get_db();
+
+    $missing = validate_required($input, ['task_id', 'author_name', 'browser_id']);
+    if (!empty($missing)) {
+        error_response('Missing Fields: ' . implode(', ', $missing));
+    }
+
+    // Checks if Task exists and is open
+    $stmt = $pdo->prepare("SELECT task_id, status FROM tasks WHERE task_id = :id");
+    $stmt->execute([':id' => $input['task_id']]);
+    $task = $stmt->fetch();
+
+    if (!$task) {
+        error_response('Task not found.', 404);
+    }
+    if ($task['status'] !== 'open') {
+        error_response('Task is not available for Completion.');
+    }
+
+    // Handles required Completion Photo
+    if (!isset($_FILES['completion_photo']) || $_FILES['completion_photo']['error'] !== UPLOAD_ERR_OK) {
+        error_response('Completion Photo is required.');
+    }
+
+    $photo_path = handle_photo_upload($_FILES['completion_photo']);
+    if (!$photo_path) {
+        error_response('Photo Upload failed. JPG, PNG, GIF and WebP up to 5 MB.');
+    }
+
+    try {
+        $stmt = $pdo->prepare("
+            UPDATE tasks SET
+                status = 'completed',
+                completed_by_name = :name,
+                completed_by_browser = :browser,
+                completion_photo = :photo,
+                completion_comment = :comment,
+                completed_at = NOW()
+            WHERE task_id = :id
+        ");
+        $stmt->execute([
+            ':id'      => $input['task_id'],
+            ':name'    => $input['author_name'],
+            ':browser' => $input['browser_id'],
+            ':photo'   => $photo_path,
+            ':comment' => $input['completion_comment'] ?? ''
+        ]);
+
+        json_response(['message' => 'Task Completion submitted for Review.']);
+
+    } catch (PDOException $e) {
+        error_response('Database Error: ' . $e->getMessage(), 500);
+    }
+}
+
+
+// ---------------------------------------------------------------------
+// VERIFY TASK: Moderator confirms or rejects Completions
+// Required: task_id, action
+// Awards Points and sets Status if verified
+// Clears Completion Fields, resets Status if rejected
+// ---------------------------------------------------------------------
+function handle_verify_task($input) {
+    $pdo = get_db();
+
+    $missing = validate_required($input, ['task_id', 'verify_action']);
+    if (!empty($missing)) {
+        error_response('Missing Fields: ' . implode(', ', $missing));
+    }
+
+    // Loads Task
+    $stmt = $pdo->prepare("SELECT * FROM tasks WHERE task_id = :id");
+    $stmt->execute([':id' => $input['task_id']]);
+    $task = $stmt->fetch();
+
+    if (!$task) {
+        error_response('Task not found.', 404);
+    }
+    if ($task['status'] !== 'completed') {
+        error_response('Task is not in completed State.');
+    }
+
+    try {
+        if ($input['verify_action'] === 'verify') {
+            // Accepts Completion and Awards Points
+            $stmt = $pdo->prepare("UPDATE tasks SET status = 'verified' WHERE task_id = :id");
+            $stmt->execute([':id' => $input['task_id']]);
+
+            // Awards Points to User
+            $stmt = $pdo->prepare("
+                INSERT INTO user_points (municipality_id, user_name, points, task_id)
+                VALUES (:mid, :name, :points, :tid)
+            ");
+            $stmt->execute([
+                ':mid'    => $task['municipality_id'],
+                ':name'   => $task['completed_by_name'],
+                ':points' => $task['points_reward'],
+                ':tid'    => $input['task_id']
+            ]);
+
+            json_response(['message' => 'Task verified. Points awarded.']);
+
+        } elseif ($input['verify_action'] === 'reject') {
+            // Rejects Completion and Clears Fields
+            $stmt = $pdo->prepare("
+                UPDATE tasks SET
+                    status = 'open',
+                    completed_by_name = NULL,
+                    completed_by_browser = NULL,
+                    completion_photo = NULL,
+                    completion_comment = NULL,
+                    completed_at = NULL
+                WHERE task_id = :id
+            ");
+            $stmt->execute([':id' => $input['task_id']]);
+
+            json_response(['message' => 'Completion rejected. Task is open again.']);
+
+        } else {
+            error_response('Invalid Action. Must be: verify or reject.');
+        }
+
+    } catch (PDOException $e) {
+        error_response('Database Error: ' . $e->getMessage(), 500);
+    }
+}
+
+
+// ---------------------------------------------------------------------
+// READ LEADERBOARD: Returns Citizen Leaderboard
+// Required: municipality_id
+// Optional: limit
+// ---------------------------------------------------------------------
+function handle_read_leaderboard($input) {
+    $pdo = get_db();
+
+    $missing = validate_required($input, ['municipality_id']);
+    if (!empty($missing)) {
+        error_response('Missing Fields: ' . implode(', ', $missing));
+    }
+
+    $limit = min((int)($input['limit'] ?? 10), 50);
+
+    try {
+        $stmt = $pdo->prepare("
+            SELECT user_name,
+                   SUM(points) AS total_points,
+                   COUNT(*) AS tasks_completed
+            FROM user_points
+            WHERE municipality_id = :mid
+            GROUP BY user_name
+            ORDER BY total_points DESC
+            LIMIT :lim
+        ");
+        $stmt->bindValue(':mid', $input['municipality_id'], PDO::PARAM_INT);
+        $stmt->bindValue(':lim', $limit, PDO::PARAM_INT);
+        $stmt->execute();
+
+        json_response(['leaderboard' => $stmt->fetchAll()]);
+
+    } catch (PDOException $e) {
+        error_response('Database Error: ' . $e->getMessage(), 500);
+    }
+}

public/api/db.php

@@ -111,3 +111,21 @@ function get_categories() {
         'other'       => ['label' => 'Sonstiges',   'faIcon' => 'fa-thumbtack',     'color' => '#7F7F7F'],
     ];
 }
+
+// ---------------------------------------------------------------------
+// Task Category Definitions
+// Returns associative Array of Task Category Keys to Labels, Icons,
+// and Colors. Shared between Citizen Participation Portal and
+// Moderation Page.
+// ToDo: Move to Database Table. 
+// ---------------------------------------------------------------------
+function get_task_categories() {
+    return [
+        'repair'     => ['label' => 'Reparatur',       'faIcon' => 'fa-wrench',         'color' => '#C00000'],
+        'social'     => ['label' => 'Nachbarschaft',   'faIcon' => 'fa-people-group',   'color' => '#E65100'],
+        'safety'     => ['label' => 'Sicherheit',      'faIcon' => 'fa-shield-halved',  'color' => '#FFC000'],
+        'greenery'   => ['label' => 'Grünpflege',      'faIcon' => 'fa-leaf',           'color' => '#92D050'],
+        'cleanup'    => ['label' => 'Sauberkeit',      'faIcon' => 'fa-broom',          'color' => '#0070C0'],
+        'other_task' => ['label' => 'Sonstiges',       'faIcon' => 'fa-clipboard-check','color' => '#7F7F7F'],
+    ];
+}