-- subagents/frontmatter.lua: splitting a profile into YAML header and body.
--
-- The body is the part a broken header must never cost the user, so every
-- degraded case is checked for "body preserved verbatim" as well as for the
-- warning. Cases that actually parse YAML need tinyyaml and skip without it.

local frontmatter = require("subagents.frontmatter")

local function yaml_or_skip()
    return pcall(require, "tinyyaml")
end

return {
    { "fenced header parses and keeps the body verbatim", function()
        if not yaml_or_skip() then
            return "skip", "tinyyaml is not installed"
        end
        local body = "You are a reviewer.\n\n  indented line  \n"
        local data, parsed_body, warning = frontmatter.parse(
            "---\nname: reviewer\ndescription: Reviews changes\nmodel: anthropic:sonnet\n---\n" .. body)
        assert(warning == nil, "unexpected warning: " .. tostring(warning))
        assert(type(data) == "table", "expected a mapping")
        assert(data.name == "reviewer", tostring(data.name))
        assert(data.description == "Reviews changes")
        assert(data.model == "anthropic:sonnet", tostring(data.model))
        assert(parsed_body == body, string.format("body was rewritten: %q", parsed_body))
    end },

    { "CRLF fences are tolerated", function()
        if not yaml_or_skip() then
            return "skip", "tinyyaml is not installed"
        end
        local data, body, warning = frontmatter.parse("---\r\nname: crlf\r\n---\r\nbody\r\n")
        assert(warning == nil, tostring(warning))
        assert(type(data) == "table" and data.name == "crlf", "header did not parse")
        assert(body == "body\r\n", string.format("%q", body))
    end },

    { "no fence means the whole file is the body", function()
        local text = "You are a reviewer.\n\n---\n\nNot a header.\n"
        local data, body, warning = frontmatter.parse(text)
        assert(data == nil, "expected no metadata")
        assert(body == text, "body was rewritten")
        assert(warning == nil, tostring(warning))
    end },

    { "an unterminated fence is treated as prose", function()
        local text = "---\nname: never closed\n\nstill prose\n"
        local data, body, warning = frontmatter.parse(text)
        assert(data == nil, "expected no metadata")
        assert(body == text, "body was rewritten")
        assert(warning == nil, "a lone rule is not an error")
    end },

    { "an empty fenced block is an empty mapping", function()
        local data, body, warning = frontmatter.parse("---\n---\nbody\n")
        assert(type(data) == "table" and next(data) == nil, "expected an empty mapping")
        assert(body == "body\n", string.format("%q", body))
        assert(warning == nil, tostring(warning))
    end },

    { "a header the parser rejects warns and keeps the body", function()
        if not yaml_or_skip() then
            return "skip", "tinyyaml is not installed"
        end
        local data, body, warning = frontmatter.parse("---\njust a string\n---\nbody\n")
        assert(data == nil, "a rejected header must not produce metadata")
        assert(body == "body\n", string.format("%q", body))
        assert(type(warning) == "string" and warning:find("did not parse", 1, true),
            "expected a parse warning, got " .. tostring(warning))
    end },

    { "an unresolved alias is dropped rather than read literally", function()
        if not yaml_or_skip() then
            return "skip", "tinyyaml is not installed"
        end
        -- tinyyaml does not resolve aliases: without the guard in parse(), the
        -- `*d` token would arrive as the literal string "*d" and become this
        -- profile's name.
        local data, body, warning = frontmatter.parse(
            "---\ndefs: &d my-agent\nname: *d\n---\nbody\n")
        assert(type(data) == "table", "the mapping itself should survive")
        assert(data.name == nil, "an alias must not become a value, got " .. tostring(data.name))
        assert(data.defs == nil, "an anchor must not become a value, got " .. tostring(data.defs))
        assert(body == "body\n", string.format("%q", body))
        assert(type(warning) == "string" and warning:find("anchors/aliases", 1, true),
            "expected an alias warning, got " .. tostring(warning))
    end },

    { "empty input is empty output", function()
        local data, body, warning = frontmatter.parse("")
        assert(data == nil and body == "" and warning == nil)
    end },
}