-- Migration: Create chat tables (conversations, messages)
-- Description: Stores chat history for candidate-company communication

CREATE TABLE IF NOT EXISTS conversations (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v7(),
    candidate_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    company_id UUID NOT NULL REFERENCES companies(id) ON DELETE CASCADE,
    job_id UUID REFERENCES jobs(id) ON DELETE SET NULL,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
    last_message TEXT,
    last_message_at TIMESTAMP WITH TIME ZONE
);

CREATE INDEX idx_conversations_candidate ON conversations(candidate_id);
CREATE INDEX idx_conversations_company ON conversations(company_id);
CREATE INDEX idx_conversations_updated ON conversations(updated_at DESC);

CREATE TABLE IF NOT EXISTS messages (
    id UUID PRIMARY KEY DEFAULT uuid_generate_v7(),
    conversation_id UUID NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
    sender_id UUID NOT NULL REFERENCES users(id),
    content TEXT NOT NULL,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
    appwrite_id VARCHAR(255)
);

CREATE INDEX idx_messages_conversation ON messages(conversation_id);
CREATE INDEX idx_messages_created ON messages(created_at);

COMMENT ON TABLE conversations IS 'Chat conversations between candidates and companies';
COMMENT ON TABLE messages IS 'Individual chat messages synchronized with Appwrite';