feat: implement chat and conversation history management with database schema and API endpoints

db/migrations/0000015_chat_and_support.down.sql

@@ -0,0 +1,3 @@
+DROP TABLE IF EXISTS chatbot_histories CASCADE;
+DROP TABLE IF EXISTS messages CASCADE;
+DROP TABLE IF EXISTS conversations CASCADE;

db/migrations/0000015_chat_and_support.up.sql

@@ -0,0 +1,34 @@
+CREATE TABLE IF NOT EXISTS conversations (
+    id UUID PRIMARY KEY DEFAULT uuidv7(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    mod_id UUID REFERENCES users(id) ON DELETE SET NULL,
+    status SMALLINT NOT NULL DEFAULT 1, -- 1: waiting, 2: active, 3: resolved
+    closed_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_conversations_user_id ON conversations (user_id);
+CREATE INDEX idx_conversations_mod_id ON conversations (mod_id);
+CREATE INDEX idx_conversations_status ON conversations (status);
+
+CREATE TABLE IF NOT EXISTS messages (
+    id UUID PRIMARY KEY DEFAULT uuidv7(),
+    conversation_id UUID NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
+    sender_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    content TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_messages_conversation_id ON messages (conversation_id);
+CREATE INDEX idx_messages_created_at ON messages (created_at DESC);
+
+CREATE TABLE IF NOT EXISTS chatbot_histories (
+    id UUID PRIMARY KEY DEFAULT uuidv7(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    question TEXT NOT NULL,
+    answer TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_chatbot_histories_user_id ON chatbot_histories (user_id, created_at DESC);

db/query/chat.sql

@@ -0,0 +1,46 @@
+-- name: CreateConversation :one
+INSERT INTO conversations (user_id, status)
+VALUES ($1, $2)
+RETURNING *;
+
+-- name: UpdateConversationStatus :one
+UPDATE conversations
+SET status = $2, mod_id = COALESCE($3, mod_id), closed_at = $4, updated_at = NOW()
+WHERE id = $1
+RETURNING *;
+
+-- name: CreateMessage :one
+INSERT INTO messages (conversation_id, sender_id, content)
+VALUES ($1, $2, $3)
+RETURNING *;
+
+-- name: GetMessagesByConversation :many
+SELECT * FROM messages
+WHERE conversation_id = $1
+  AND (sqlc.narg('cursor_id')::uuid IS NULL OR id < sqlc.narg('cursor_id')::uuid)
+ORDER BY created_at DESC
+LIMIT sqlc.arg('limit');
+
+-- name: GetConversationsByIDs :many
+SELECT * FROM conversations WHERE id = ANY($1::uuid[]);
+
+-- name: GetMessagesByIDs :many
+SELECT * FROM messages WHERE id = ANY($1::uuid[]);
+
+-- name: CreateChatbotHistory :one
+INSERT INTO chatbot_histories (user_id, question, answer)
+VALUES ($1, $2, $3)
+RETURNING *;
+
+-- name: GetChatbotHistory :many
+SELECT * FROM (
+    SELECT * FROM chatbot_histories
+    WHERE user_id = $1
+      AND (sqlc.narg('cursor_id')::uuid IS NULL OR id < sqlc.narg('cursor_id')::uuid)
+    ORDER BY created_at DESC
+    LIMIT sqlc.arg('limit')
+) sub
+ORDER BY created_at ASC;
+
+-- name: GetChatbotHistoriesByIDs :many
+SELECT * FROM chatbot_histories WHERE id = ANY($1::uuid[]);

db/schema.sql

@@ -208,3 +208,30 @@ CREATE TABLE IF NOT EXISTS system_statistics (
 
     created_at TIMESTAMPTZ DEFAULT now()
 );
+
+CREATE TABLE IF NOT EXISTS conversations (
+    id UUID PRIMARY KEY DEFAULT uuidv7(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    mod_id UUID REFERENCES users(id) ON DELETE SET NULL,
+    status SMALLINT NOT NULL DEFAULT 1,
+    closed_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS messages (
+    id UUID PRIMARY KEY DEFAULT uuidv7(),
+    conversation_id UUID NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
+    sender_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    content TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS chatbot_histories (
+    id UUID PRIMARY KEY DEFAULT uuidv7(),
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    question TEXT NOT NULL,
+    answer TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+