-- V19: Markdown Links (Obsidian-style bidirectional links)
-- Adds support for wikilinks, markdown links, embeds, and backlink tracking

-- Table for storing extracted markdown links
CREATE TABLE IF NOT EXISTS markdown_links (
    id TEXT PRIMARY KEY NOT NULL,
    source_media_id TEXT NOT NULL,
    target_path TEXT NOT NULL,           -- raw link target (wikilink or path)
    target_media_id TEXT,                -- resolved media_id (nullable if unresolved)
    link_type TEXT NOT NULL,             -- 'wikilink', 'markdown_link', 'embed'
    link_text TEXT,                      -- display text for the link
    line_number INTEGER,                 -- line number in source file
    context TEXT,                        -- surrounding text for preview
    created_at TEXT NOT NULL,
    FOREIGN KEY (source_media_id) REFERENCES media_items(id) ON DELETE CASCADE,
    FOREIGN KEY (target_media_id) REFERENCES media_items(id) ON DELETE SET NULL
);

-- Index for efficient outgoing link queries (what does this note link to?)
CREATE INDEX idx_links_source ON markdown_links(source_media_id);

-- Index for efficient backlink queries (what links to this note?)
CREATE INDEX idx_links_target ON markdown_links(target_media_id);

-- Index for path-based resolution (finding unresolved links)
CREATE INDEX idx_links_target_path ON markdown_links(target_path);

-- Index for link type filtering
CREATE INDEX idx_links_type ON markdown_links(link_type);

-- Track when links were last extracted from a media item
ALTER TABLE media_items ADD COLUMN links_extracted_at TEXT;

-- Index for finding media items that need link extraction
CREATE INDEX idx_media_links_extracted ON media_items(links_extracted_at);