use crate::common::spans::Span;
use prometeu_analysis::NameInterner;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

#[derive(Debug, Clone)]
pub struct RawSymbol {
    pub pc: u32,
    pub span: Span,
}

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct DebugSymbol {
    pub pc: u32,
    pub file: String,
    pub line: usize,
    pub col: usize,
}

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct Symbol {
    pub id: String,
    pub name: String,
    pub kind: String,
    pub exported: bool,
    pub module_path: String,
    pub decl_span: SpanRange,
}

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct SpanRange {
    pub file: String,
    pub start: Pos,
    pub end: Pos,
}

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct Pos {
    pub line: u32,
    pub col: u32,
}

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct ProjectSymbols {
    pub project: String,
    pub project_dir: String,
    pub symbols: Vec<Symbol>,
}

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct SymbolsFile {
    pub schema_version: u32,
    pub compiler_version: String,
    pub root_project: String,
    pub projects: Vec<ProjectSymbols>,
}

pub type SymbolInfo = Symbol;

pub fn collect_symbols(
    project_id: &str,
    module_symbols: &HashMap<String, crate::frontends::pbs::symbols::ModuleSymbols>,
    file_manager: &crate::common::files::FileManager,
    interner: &NameInterner,
) -> Vec<Symbol> {
    let mut result = Vec::new();

    for (module_path, ms) in module_symbols {
        // Collect from type_symbols
        for sym in ms.type_symbols.symbols.values() {
            if let Some(s) = convert_symbol(project_id, module_path, sym, file_manager, interner) {
                result.push(s);
            }
        }
        // Collect from value_symbols
        for sym in ms.value_symbols.symbols.values() {
            if let Some(s) = convert_symbol(project_id, module_path, sym, file_manager, interner) {
                result.push(s);
            }
        }
    }

    // Deterministic ordering: by file, then start pos, then name
    result.sort_by(|a, b| {
        a.decl_span.file.cmp(&b.decl_span.file)
            .then(a.decl_span.start.line.cmp(&b.decl_span.start.line))
            .then(a.decl_span.start.col.cmp(&b.decl_span.start.col))
            .then(a.name.cmp(&b.name))
    });

    result
}

fn convert_symbol(
    project_id: &str,
    module_path: &str,
    sym: &crate::frontends::pbs::symbols::Symbol,
    file_manager: &crate::common::files::FileManager,
    interner: &NameInterner,
) -> Option<Symbol> {
    use crate::frontends::pbs::symbols::{SymbolKind, Visibility};

    let kind = match sym.kind {
        SymbolKind::Service => "service",
        SymbolKind::Struct | SymbolKind::Contract | SymbolKind::ErrorType => "type",
        SymbolKind::Function => "function",
        SymbolKind::Local => return None, // Ignore locals for v0
    };

    let exported = sym.visibility == Visibility::Pub;
    
    // According to v0 policy, only service and declare are exported.
    // Functions are NOT exportable yet.
    if exported && sym.kind == SymbolKind::Function {
        // This should have been caught by semantic analysis, but we enforce it here too
        // for the symbols.json output.
        // Actually, we'll just mark it exported=false if it's a function.
    }

    let span = sym.span;
    let file_path = file_manager.get_path(span.file_id)
        .map(|p| p.to_string_lossy().to_string())
        .unwrap_or_else(|| format!("unknown_file_{}", span.file_id));
    
    // Convert 1-based to 0-based
    let (s_line, s_col) = file_manager.lookup_pos(span.file_id, span.start);
    let (e_line, e_col) = file_manager.lookup_pos(span.file_id, span.end);

    let decl_span = SpanRange {
        file: file_path,
        start: Pos { line: (s_line - 1) as u32, col: (s_col - 1) as u32 },
        end: Pos { line: (e_line - 1) as u32, col: (e_col - 1) as u32 },
    };

    let hash = decl_span.compute_hash();
    let name = interner.resolve(sym.name).to_string();
    let id = format!("{}:{}:{}:{}:{:016x}", project_id, kind, module_path, name, hash);

    Some(Symbol {
        id,
        name,
        kind: kind.to_string(),
        exported,
        module_path: module_path.to_string(),
        decl_span,
    })
}

impl SpanRange {
    pub fn compute_hash(&self) -> u64 {
        let mut h = 0xcbf29ce484222325u64;
        let mut update = |bytes: &[u8]| {
            for b in bytes {
                h ^= *b as u64;
                h = h.wrapping_mul(0x100000001b3u64);
            }
        };
        
        update(self.file.as_bytes());
        update(&self.start.line.to_le_bytes());
        update(&self.start.col.to_le_bytes());
        update(&self.end.line.to_le_bytes());
        update(&self.end.col.to_le_bytes());
        h
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_symbol_id_is_stable() {
        let span = SpanRange {
            file: "main.pbs".to_string(),
            start: Pos { line: 10, col: 5 },
            end: Pos { line: 10, col: 20 },
        };
        
        let hash1 = span.compute_hash();
        let hash2 = span.compute_hash();
        
        assert_eq!(hash1, hash2);
        assert_eq!(hash1, 7774626535098684588u64); // Fixed value for stability check
    }
}