INSTALL duck_block_utils FROM community;
LOAD duck_block_utils;

-- Build a document programmatically
SELECT duck_blocks_assemble([
    duck_block_heading(1, 'Hello World'),
    duck_block_paragraph([
        duck_block_text('This is '),
        duck_block_bold('important'),
        duck_block_text(' content.')
    ]),
    duck_block_code('sql', 'SELECT * FROM documents')
]);

-- Render it as plain text
SELECT duck_blocks_to_text(duck_blocks_assemble([
    duck_block_heading(1, 'Hello World'),
    duck_block_paragraph('Some prose.')
]));

-- Works with the markdown extension for reading and writing files
LOAD markdown;
LOAD duck_block_utils;

-- Table of contents from a markdown file
SELECT * FROM duck_blocks_toc_rows(
    (SELECT list(b) FROM read_markdown_blocks('README.md') b)
);

-- Validate document structure
SELECT duck_blocks_validate(
    (SELECT list(b) FROM read_markdown_blocks('doc.md') b)
);

db_heading(1, 'Title')      ->  duck_block_heading(1, 'Title')
db_assemble(blocks)         ->  duck_blocks_assemble(blocks)
db_blocks_to_text(blocks)   ->  duck_blocks_to_text(blocks)
db_page                     ->  page_break

STRUCT(
    kind VARCHAR,                       -- 'block', 'inline' or 'value'
    element_type VARCHAR,               -- 'heading', 'paragraph', 'bold', 'link', etc.
    content VARCHAR,                    -- text, iff the element has a single text child
    level INTEGER,                      -- depth in a depth-first ordering; top is 1 (0 is the
                                        --   optional explicit document root)
    encoding VARCHAR,                   -- 'text', 'json', 'yaml', 'html', 'xml',
                                        --   'latex', 'markdown', 'toml'
    attributes MAP(VARCHAR, VARCHAR),   -- element-specific metadata
    element_order INTEGER               -- position in the document
)

SELECT duck_block_paragraph([
    duck_block_text('Click '),
    duck_block_link('https://example.com', 'here'),
    duck_block_text(' for more.')
]);

-- Read markdown, append to it, write it back
LOAD markdown;
LOAD duck_block_utils;

COPY (
    SELECT unnest(duck_blocks_concat(
        (SELECT list(b) FROM read_markdown_blocks('doc.md') b),
        duck_blocks_assemble([
            duck_block_hr(),
            duck_block_paragraph('Generated by DuckDB')
        ])
    )) AS block
) TO 'output.md' (FORMAT markdown, MARKDOWN_MODE duck_block);